> -----Original Message-----
> From: Xiaohui Zhang <[email protected]>
> Sent: Tuesday, December 8, 2020 5:19 AM
> To: Xiaohui Zhang <[email protected]>; KY Srinivasan
> <[email protected]>; Haiyang Zhang <[email protected]>; Stephen
> Hemminger <[email protected]>; Wei Liu <[email protected]>;
> James E.J. Bottomley <[email protected]>; Martin K. Petersen
> <[email protected]>; [email protected]; linux-
> [email protected]; [email protected]
> Subject: [EXTERNAL] [PATCH 1/1] scsi: Fix possible buffer overflows in
> storvsc_queuecommand
>
> From: Zhang Xiaohui <[email protected]>
>
> storvsc_queuecommand() calls memcpy() without checking the destination size
> may trigger a buffer overflower, which a local user could use to cause denial of
> service or the execution of arbitrary code.
> Fix it by putting the length check before calling memcpy().
>
> Signed-off-by: Zhang Xiaohui <[email protected]>
> ---
> drivers/scsi/storvsc_drv.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c index
> 0c65fbd41..09b60a4c0 100644
> --- a/drivers/scsi/storvsc_drv.c
> +++ b/drivers/scsi/storvsc_drv.c
> @@ -1729,6 +1729,8 @@ static int storvsc_queuecommand(struct Scsi_Host
> *host, struct scsi_cmnd *scmnd)
>
> vm_srb->cdb_length = scmnd->cmd_len;
>
> + if (vm_srb->cdb_length > STORVSC_MAX_CMD_LEN)
> + vm_srb->cdb_length = STORVSC_MAX_CMD_LEN;
> memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
The data structure is sized correctly to handle the max command length. Besides
your check is bogus - you cannot truncate the command!
K. Y
>
> sgl = (struct scatterlist *)scsi_sglist(scmnd);
> --
> 2.17.1